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Report released on the effects of climate change on agriculture

A report entitled "The Effects of Climate Change on Agriculture, Land Resources, Water Resources and Biodiversity in the United States" was released today by the U.S. Climate Change Science Program. Among other findings, the report predicts that grain and oilseed crops will mature more rapidly and the risk of crop failures will be higher.

May 27, 2008  By USDA

May 27, 2008


Washington — The U.S. Climate
Change Science Program (CCSP) today released "Synthesis and Assessment
Product 4.3 (
SAP 4.3): The Effects of
Climate Change on Agriculture, Land Resources, Water Resources, and
Biodiversity in the
United States." The CCSP
integrates the federal research efforts of 13 agencies on climate and global
change. Today's report is one of the most extensive examinations of climate
impacts on
U.S. ecosystems. USDA is
the lead agency for this report and coordinated its production as part of its
commitment to CCSP.


report issued today provides practical information that will help land owners
and resource managers make better decisions to address the risks of climate
change," said Agriculture Chief Economist Joe Glauber.

The report
was written by 38 authors from the universities, national laboratories,
non-governmental organizations, and federal service. The report underwent
expert peer review by 14 scientists through a Federal Advisory Committee
formed by the USDA. The
National Center for Atmospheric
Research also coordinated in the production of the report. It is posted on
the CCSP Web site at:

The report
finds that climate change is already affecting
U.S. water resources,
agriculture, land resources, and biodiversity, and will continue to do so.
Specific findings include:

  • Grain and oilseed crops will
    mature more rapidly, but increasing temperatures will increase the risk
    of crop failures, particularly if precipitation decreases or becomes
    more variable.
  • Higher temperatures will
    negatively affect livestock. Warmer winters will reduce mortality but
    this will be more than offset by greater mortality in hotter summers.
    Hotter temperatures will also result in reduced productivity of
    livestock and dairy animals.
  • Forests in the interior West,
    the Southwest, and
    Alaska are already being affected
    by climate change with increases in the size and frequency of forest
    fires, insect outbreaks and tree mortality. These changes are expected
    to continue.
  • Much of the United States has experienced higher
    precipitation and streamflow, with decreased drought severity and
    duration, over the 20th century. The West and Southwest, however, are
    notable exceptions, and increased drought conditions have occurred in
    these regions.
  • Weeds grow more rapidly under
    elevated atmospheric CO2. Under projections reported in the assessment,
    weeds migrate northward and are less sensitive to herbicide
  • There is a trend toward
    reduced mountain snowpack and earlier spring snowmelt runoff in the
    Western United States.
  • Horticultural crops (such as
    tomato, onion, and fruit) are more sensitive to climate change than
    grains and oilseed crops.
  • Young forests on fertile
    soils will achieve higher productivity from elevated atmospheric CO2
    concentrations. Nitrogen deposition and warmer temperatures will
    increase productivity in other types of forests where water is
  • Invasion by exotic grass
    species into arid lands will result from climate change, causing an
    increased fire frequency. Rivers and riparian systems in arid lands will
    be negatively impacted.
  • A continuation of the trend
    toward increased water use efficiency could help mitigate the impacts of
    climate change on water resources.
  • The growing season has
    increased by 10 to 14 days over the last 19 years across the temperate latitudes.
    Species' distributions have also shifted.
  • The rapid rates of warming in
    Arctic observed in recent decades,
    and projected for at least the next century, are dramatically reducing
    the snow and ice covers that provide denning and foraging habitat for
    polar bears.

USDA agencies are responding to the risks of
climate change. For example, the Forest Service is incorporating climate
change risks into National Forest Management Plans and is providing guidance
to forest managers on how to respond and adapt to climate change. The Natural
Resources Conservation Service and Farm Services Agency are encouraging
actions to reduce greenhouse gas emissions and increase carbon sequestration
through conservation programs. USDA's Risk Management Agency has prepared
tools to manage drought risks and is conducting an assessment of the risks of
climate change on the crop insurance program.


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